The following description of background art may include insights, discoveries, understandings or disclosures, or associations together with dis-closures not known to the relevant art prior to the present invention but provided by the invention. Some such contributions of the invention may be specifically pointed out below, whereas other such contributions of the invention will be apparent from their context.
In recent years, the phenomenal growth of mobile Internet services and proliferation of smart phones and tablets has increased a demand for mobile broadband services, and hence more network capacity is required. One possibility to increase network capacity is offloading some of the macro user traffic to cells on unlicensed spectrum. For example, within the 3rd Generation Partnership Project (3GPP) specifying modern cellular communication systems, usage of additional bands for a carrier aggregation (CA) configuration has raised interest. The basic idea behind this concept is to expand bandwidth of a cellular network by accessing additional frequency bands. The cellular communication system may thus employ a primary cell (PCell) comprising a primary carrier on its licensed frequency band and create a new carrier on such an additional frequency band as a secondary cell (SCell).